Inside Earth:
Chapter 3: Volcanoes
Section 2: Volcanic Activity
Vocabulary:
Magma Chamber: Pocket of magma; formed by subduction
Pipe: Main channel where magma flows to the surface
Crater: bowl shaped area that fills up with magma at the top of a volcano
Vent: point where magma and gasses leave the volcano
Lava Flow: when lava flows over the sides of the volcano out of a vent
Side Vent: opening in the side of a volcano; lava escapes through these
vents
Silica: material formed from oxygen and silicone; one of the most abundant
materials in Earth’s mantle and crust
Pahoehoe: fast moving, hot lava
aa: slow moving, cooled lava
Side Vent: occurs when an explosive eruption hurls out ash, cinders, bombs,
and gasses
Hot Spring: forms when groundwater heated by nearby magma, rises to the
surface and collects in a natural pool
Geothermal Energy: a clean, reliable energy source caused when water is
heated by magma
 During a volcanic eruption, the gasses dissolved in magma rush out,
carrying the magma with them
 The silica content of magma helps to determine whether the volcanic
eruption is quiet or explosive
 Magma rises through the lithosphere because it is less dense and it is
rising through the solid rock. As the magma materials rise, the rock
cracks and magma goes through.
 Both quiet and explosive eruptions can cause damage far from the
crater’s rim.
 3 Stages of a Volcano
o Active- it will erupt or is erupting
o Dormant- there is a possibility that it will erupt (may not be for
a long time)
o Extinct- it will not erupt